I keep hearing these noises in my head!

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Aug 8, 2006
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Hello to everyone!
I have a question that I hope someone may be able to help me with. I have been hearing this rattle/tap in the top end for about a month, not really bad, but bad enough.
I figured that the valves just needed a little tightening so last night I took a look. The adjustments were pretty close but what has me concerned is that one of the intake rockers pushes the valve down ALOT further than the other.
I never noticed this before, and was wondering if this could be the issue. also, what could cause this? Push rod is all that I can come up with. I remember that the ends of the alloy push rods spun when I installed them about 7 years ago and I haven't had a reason to remove the head since. Has anyone ever had one of these ball ends come loose? Bent rod maybe?
My bike doesn't have a mushy cam so I am kind of stumped by this. I'm sure that the stock valve springs could use a break, but valve float isn't a issue. I know that I gotta take her down this winter so I will for sure find out then. Maybe one of you has experienced this and can point me in the right direction.
Also, has anyone used those bronze exhaust locking rings? They ain't supposed to come loose, do they work? is there an affordable source in the USA? I think that they look pretty cool, and I would have no problem getting rid of the stock steel ones.
Mark, as long as you have the correct clearance at the valve stem then the problem unlikely to be a push rod end that has moved. The amount of lift is generally governed by the cam shaft lobes and not by the push rod length, theoretically if you had push rods 100 feet long the up and down movement would still be the same although obviously it wouldn't fit very well in the head and you might have trouble riding under low bridges! My suspicion unfortunately would be a cam shaft lobe which will necesitate removal of the head and barrel to check. Wear on one or more of these lobes is not uncommon as once the case hardening is worn through the material rapidly wears away. I would start by checking left and right push rod movement rather than valve movement. It is possible for the push-rods to move the same amount but the valves to move different amounts if for example one of the valves was bent or not seating properly although i would expect there to be a large clearance at the valve if this occured suddenly. another possibility is the use of a different length of rocker from one side to the other if the head had ever been assembled prior to your ownership with mismatched parts. I would reccomend getting to the bottom of this before riding the bike again as if it is a worn cam-shaft the shavings will be happily swimming round inside the oil galleries. The good news is that the bronze lock rings do work and i think they look great too. Best of luck
Dave: The oil is clean (no shavings). The rockers are the same, and The push rods are the same length and the adjusters are the same. I understand how the valve system works (cams, rods, rockers and all). the only variables I can see in the system are lobe height and those loose hardened caps.
The cam losing temper is not what I wanted to hear but I kind of expected as much. Have you heard of a cam losing about 3/16ths in lift without shavings in the oil? I never have.
Cam lobes can lose quite a lot without nearly as big a "christmas tree" on the magnetic plug as you might expect. the particles are very fine and probably find their way to the filter.

I have become quite an expert in self-delusion with the disappearing lobe syndrome and it can go on for quite a while before the denial has to stop !

If the problem is one of reduced lift rather than huge tappet clearances, then it really has to be a cam lobe thing. It's not the drive side exhaust by any chance is it ? (That's the one that my engines eat :( )
79x100 said:
I have become quite an expert in self-delusion with the disappearing lobe syndrome and it can go on for quite a while before the denial has to stop !

Ths is the path that I have been heading down, (the river of denial). It's the drive side intake.

I guess it's time to order a gasket set then go inside for a look. The PO gave me a recept for a megacycle cam and tappet refacing. I have always thought of that as the fix for the soft cam syndrome. I guess nothing is a sure thing.

Oh well, 7 years without being apart and 15,000 miles of two up riding across the great american southwest, something was due to wear out.
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